The majority of people in the industrialized world have access to an abundance of inexpensive processed food products. The safety, quality, and wholesomeness of these products are usually unquestioned. The availability of inexpensive food products is largely a result of advances in farm mechanization and improved industries of scale in food processing and distribution operations. The mechanization of the family farm has not come without certain drawbacks however. One of the drawbacks of large-scale food processing operations, and of meat processing in particular, is the occasional contamination (e.g., bacterial, fungal, etc.) and subsequent distribution of large quantities of contaminated products sometimes with dire consequences. Food safety researchers have determined that the introduction of even a few contaminated carcasses into the production lines of large scale food processing operations is often enough to contaminate entire batches of product. The meat packing industry is particularly susceptible to carcass contamination during dehiding, evisceration, splitting, chilling, and fabrication. Further contamination of previously uncontaminated meat products may occur during grinding, processing, and transport. This type of contamination has lead to several major meat product recalls, including the recall of 24 million pounds of ground beef by the Hudson Beef Co. in 1997, and more recently, the recall of 19 million pounds of beef and related products by the ConAgra Beef Company in July 2002. (See, Recall Release, FSIS-RC-055-2002). The economic impact of food safety and spoilage is very large. USDA ERS estimates that the leading six bacterial food borne pathogens cause $2.9-6.7 billion in medical costs and lost productivity annually in the US (Buzby et al., Bacterial Foodborne Disease: Medical Costs and Productivity Losses. 1996. Food and Consumer Economics Division, Economic Research Service U.S. Department of Agriculture. Agricultural Economic Report 741)
Many meat product recalls are the result of contamination by the bacterium Escherichia coli O157:H7. This bacterium is commonly isolated from the gastrointestinal tract and feces of cattle. Direct contact with cattle can be a source of human infection. However, the principal route of transmission to humans is through fecal contamination of carcasses at slaughter. (J. Tuttle et al., Epidemiol Infect., 122:185-192 [1999]). Every year in the United States the O157:H7 bacterium causes about 70,000 cases of hemorrhagic diarrhea and renal disease. Children, the elderly, and the immunocompromised are most susceptible to foodborne illness caused by Escherichia coli O157:H7. Virulent strains of Escherichia coli are not the only foodborne pathogens of concern.
Listeria monocytogenes has emerged as another dangerous, but relatively uncommon foodborne pathogen. Despite being an uncommon source of illness, L. monocytogenes is ubiquitous in agricultural and food processing environments and can cause serious human and animal infections. The infection caused by L. monocytogenes is commonly called Listeriosis. Listeriosis occurs in sporadic and epidemic forms throughout the world. (See e.g., B. Lorber, Clin. Infect. Dis., 24(1): 1-9 [1997]; J. M. Farber et al., Microbiol. Rev., 55:476-511 [1991]; and W. F. Schlech, Clin. Infect. Dis., 31:770-775 [2000]). A multistate outbreak of Listeriosis has been reported in the United States. (Morb. Mortal. Wkly. Report, 49(50):1129-1130 [2000] erratum in Morb. Mortal. Wkly. Report, 50(6):101 [2001]). Since May 2000, 29 illnesses caused by a strain of Listeria monocytogenes have been identified in 10 states: New York (15 cases); Georgia (3 cases); Connecticut, Ohio, and Michigan (2 cases each); and California, Pennsylvania, TennesSee, Utah, and Wisconsin (1 case each).
Listeriosis, in its most severe form, is an invasive disease that affects immunocompromised patients and has the highest case-fatality rate of any foodborne illnesses. (B. G. Gellin et al., Amer. J. Epidemiol., 133:392-401 [1991]; D. B. Louria et al., Ann. NY Acad. Sci., 174:545-551 [1970]; J. McLauchlin, Epidemiol. Infect., 104:191-201 [1990]; V. Goulet and P. Marchetti, Scand. J. Infect. Dis., 28:367-374 [1996]; and C. J. Bula et al., Clin. Infect Dis., 20:66-72 [1995]). In immunocompetent persons, it can also cause severe disease as well as outbreaks of benign febrile gastroenteritis. (P. Aureli et al., New Engl. J. Med., 342:1236-41 [2000]). Another form of human disease is perinatal infection, which is associated with a high rate of fetal loss (including full-term stillbirths) and serious neonatal disease (J. McLauchlin, Epidemiol. Infect., 104:181-190 [1990]).
Most, perhaps all, of listeriosis in humans occurs after consumption of contaminated food (e.g., meat and cheese) products. (A. Schuchat et al., J. Amer. Med. Assoc., 267:2041-2045 [1992]). While uncommon, Listeriosis causes about half the foodborne disease fatalities in the US each year. Additionally, many mild cases of listeriosis and inapparent Listeria infections go unreported. For those susceptible to listeriosis, ingestion of even small doses of L. monocytogenes is often sufficient for infection. About 2,500 cases of listeriosis are reported in the US each year, of these about 20% or 500 cases are fatal.
In 1989, the USDA FSIS implemented a testing program for L. monocytogenes in cooked meat products and adopted a zero tolerance position for L. monocytogenes contamination in ready to eat products. Guidelines promulgated by the American Association of Meat Processors for current Good Manufacturing Practices for Ready to Eat meat products address the need for environmental monitoring for Listeria as a component of HACCP programs. The ecology of L. monocytogenes and its increasing prevalence and/or detection in food preparation establishments has lead to major recalls of processed meat products. In October 2002 the USDA issued a recall notice, which when further expanded, constituted the largest meat product recall on record for 28 million pounds of processed turkey products (See, USDA FSIS Recall Notification Report 090-2002 EXP Recall from Pilgrims Pride Corp dba Wampler Foods Inc. Nov. 4, 2002). The recall was in response to detection of L. monocytogenes at multiple points in the facilities and equipment used to process the recalled turkey.
A number of approaches have been tried to increase the safety and wholesomeness of the nation's meat and agricultural products. For example, some approaches have focused on the exposing food products to one or more types of pathogen destroying processes, including ionizing radiation or ultra high temperatures and pressures. (See e.g., U.S. Pat. Nos. 5,891,490; 6,013,918; 6,086,936; and 6,165,526 etc.). U.S. Pat. No. 6,165,526 is representative of these approaches. This patent describes an UV radiation and ultra high temperature method for sterilizing food products.
A number of other approaches have focused on providing mixtures of chemicals (e.g., acids, surfactants, emulsifying agents, and organic phosphates) that inactivate bacteria and bacterial spores in food products. (See e.g., U.S. Pat. Nos. 5,550,145; and 5,618,840). U.S. Pat. No. 5,618,840, for instance, describes an antibacterial oil-in-water emulsion for inhibiting the growth of Helicobacter pylori. 
The various compositions and methods previously described for food sterilization have certain advantages and certain other disadvantages. One disadvantage is that the manufacture and additional or large quantities of artificial chemicals to food products can be costly and logistically difficult. Moreover, the current chemical food sterilization agents are indiscriminate and are thus inappropriate for addition into food products such as cheese and yogurt that require the beneficial action of certain bacteria for their production. The addition of artificial chemical compounds to food products or subjecting the products to irradiation or temperature and pressure extremes can also produce unpleasant organoleptic qualities. Another disadvantage is the publics' generally negative perception of food irradiation and the addition of chemical additives.
Still other efforts have been directed to producing food washes to remove residual surface impurities such as waxes and pesticides sometimes acquired during food product production, processing, and transporting. For instance, U.S. Pat. No. 6,367,488 describes a chemical wash for fruits and vegetables made from surfactants, such as oleate, and alcohol ethoxylates, and neutralized phosphoric acid. While these washes are useful for removing surface contaminates and surface bacteria from solid food products, these compositions are inappropriate for sterilizing homogenized food products such as ground beef.
While each of these above-mentioned compositions and methods has particular advantages and disadvantages, the need still exists for compositions and methods that reduce the amount of pathogenic bacteria shed by feedlot animals (e.g., bovines, porcines, and the like), that induce immunity in feedlot animals to pathogens, and for edible compositions that safety destroy harmful foodborne pathogens.
A further major economic problem confronting the food processing industry is that of bacterial spoilage. In particular, dairy and processed meat products are susceptible to bacterial spoilage by organisms such as the Lactic acid bacteria (e.g., Lactobacillus etc.) (Kraft A A. Health hazards vs. food spoilage. Boca Raton, Fla.: CRC Press, Inc., 1992). These organisms are widely distributed in nature, and can easily out-compete other bacteria under low oxygen tension and low pH conditions that are common in processed dairy and meat foods (Stamer. Lactic acid bacteria. In: Defigueiredo M P and Splittstoesser D F eds. Westport, Conn.: AVI Publishing, 1976). Over 20% of the fruit and vegetable products harvested for human consumption are believed to be lost to post-harvest microbial spoilage (Jay, J. Modern Food Microbiology 4th ed Van Norstand Reinhold New York, 1992).